This is a note to let you know that I've just added the patch titled
dm thin: fix a race in thin_dtr
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-thin-fix-a-race-in-thin_dtr.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 17181fb7a0c3a279196c0eeb2caba65a1519614b Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Date: Wed, 5 Nov 2014 17:00:13 -0500
Subject: dm thin: fix a race in thin_dtr
From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
commit 17181fb7a0c3a279196c0eeb2caba65a1519614b upstream.
As long as struct thin_c is in the list, anyone can grab a reference of
it. Consequently, we must wait for the reference count to drop to zero
*after* we remove the structure from the list, not before.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm-thin.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3266,14 +3266,14 @@ static void thin_dtr(struct dm_target *t
struct thin_c *tc = ti->private;
unsigned long flags;
- thin_put(tc);
- wait_for_completion(&tc->can_destroy);
-
spin_lock_irqsave(&tc->pool->lock, flags);
list_del_rcu(&tc->list);
spin_unlock_irqrestore(&tc->pool->lock, flags);
synchronize_rcu();
+ thin_put(tc);
+ wait_for_completion(&tc->can_destroy);
+
mutex_lock(&dm_thin_pool_table.mutex);
__pool_dec(tc->pool);
Patches currently in stable-queue which might be from mpatocka@xxxxxxxxxx are
queue-3.18/dm-thin-fix-a-race-in-thin_dtr.patch
queue-3.18/dm-bufio-fix-memleak-when-using-a-dm_buffer-s-inline-bio.patch
queue-3.18/dcache-fix-kmemcheck-warning-in-switch_names.patch
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